3. Subject must report having moderate or severe acute pain (as determined from the Numerical Pain Rating scale (NPRS) where 0 = no pain, 10 = worst pain; subjects must have a level of 4 or more) after a pediatric surgical procedure (at baseline) that requires hospitalization. Sponsor will pre-approve a list of acceptable surgical procedures prior to study start for each site. Surgical procedures other than those on the pre-approved list may be acceptable on a case by case basis if approved by the medical monitor (MM) and sponsor.